A number of different types of shaft seals are used in providing a seal between the liquid and gas sides of a rotating shaft. These seal types include lip seals, circumferential seals, self-contained (cartridge type) face seals and ring seals. All of these seal types have disadvantages in use. For example, lip seals have shaft speed limitations as well as pressure limitations. Circumferential seals and ring seals both suffer leakage problems particularly under so-called "flooded" conditions. Existing self-contained face seals present assembly difficulties including, for example, the requrements regarding "picking up" of tightly fitting O-rings. Further, some of the seals of this type are speed limited because the centrifugal forces generated during shaft rotation tend to seriously reduce the effectiveness of the torque resistance mechanism of the seal. Further, conventional face seals occupy excessive space and some seals of this type have leakage problems resulting from the collection of sealed liquid at the inside diameter of the sealing face.
Representative shaft seals which are of a general interest insofar as the present invention is concerned include those disclosed in U.S. Pat. Nos. 2,586,739 (Summers); 2,871,040 (Payne); 3,689,083 (Greenwalt); 3,319,968 (Yost) and 3,239,232 (Anderson) although this listing is not, nor is it intended to be, exhaustive.